11DC: PDB entry 11DC

Human Slo1-PenitremA complex under divalent chelated condition - gating-ring masked out. Determined by electron microscopy at 2.58 Å resolution. Released 23 Sept 2026.

Method: Electron microscopy
Resolution: 2.58 Å
Organism: Homo sapiens
Chains: 4
Atoms: 12,327
Mol. weight: 557.1 kDa
Ligands: A1C9J, CLR, AJP, LBN
Released: 23 Sept 2026

Explore 11DC in 3D Show helices and sheets RCSB PDB PDBe

Secondary structure: helices and β-sheets

11DC contains 52 α-helices and 8 β-strands across 4 chains. Residue ranges use author residue numbering, as in the PDB file, from PDBe. To see them in 3D, choose the Cartoon representation with Secondary structure coloring: helices, sheets and coils get different colors.

Chains A, B, C and D: 13 helices, 2 β-strands

Element	Residues	Length	Sheet
α-helix	22-48	27
α-helix	94-105	12
α-helix	110-133	24
β-strand	139-141	3	1
α-helix	148-169	22
α-helix	174-177	4
α-helix	181-187	7
α-helix	190-199	10
β-strand	201-203	3	1
α-helix	207-216	10
α-helix	217-223	7
α-helix	230-259	30
α-helix	262-264	3
α-helix	274-285	12
α-helix	298-327	30

Molecules and chains

Molecule	Chains	Type	Length	Organism	UniProt
Isoform 5 of Calcium-activated potassium channel subunit alpha-1	A, B, C, D	protein	1065	Homo sapiens	Q12791 (AlphaFold model)

Sequence of entity 1 (A, B, C, D), FASTA

>11DC_1 Isoform 5 of Calcium-activated potassium channel subunit alpha-1 (chains A, B, C, D)
MDALIIPVTMEVPCDSRGQRMWWAFLASSMVTFFGGLFIILLWRTLKYLWTVCCHCGGKT
KEAQKINNGSSQADGTLKPVDEKEEAVAAEVGWMTSVKDWAGVMISAQTLTGRVLVVLVF
ALSIGALVIYFIDSSNPIESCQNFYKDFTLQIDMAFNVFFLLYFGLRFIAANDKLWFWLE
VNSVVDFFTVPPVFVSVYLNRSWLGLRFLRALRLIQFSEILQFLNILKTSNSIKLVNLLS
IFISTWLTAAGFIHLVENSGDPWENFQNNQALTYWECVYLLMVTMSTVGYGDVYAKTTLG
RLFMVFFILGGLAMFASYVPEIIELIGNRKKYGGSYSAVSGRKHIVVCGHITLESVSNFL
KDFLHKDRDDVNVEIVFLHNISPNLELEALFKRHFTQVEFYQGSVLNPHDLARVKIESAD
ACLILANKYCADPDAEDASNIMRVISIKNYHPKIRIITQMLQYHNKAHLLNIPSWNWKEG
DDAICLAELKLGFIAQSCLAQGLSTMLANLFSIRSFIKIEEDTWQKYYLEGVSNEMYTEY
LSSAFVGLSFPTVCELCFVKLKLLMIAIEYKSANRESRILINPGNHLKIQEGTLGFFIAS
DAKEVKRAFFYCKACHDDITDPKRIKKCGCKRLEDEQPSTLSPKKKQRNGGMRNSPNTSP
KLMRHDPLLIPGNDQIDNMDSNVKKYDSTGMFHWCAPKEIEKVILTRSEAAMTVLSGHVV
VCIFGDVSSALIGLRNLVMPLRASNFHYHELKHIVFVGSIEYLKREWETLHNFPKVSILP
GTPLSRADLRAVNINLCDMCVILSANQNNIDDTSLQDKECILASLNIKSMQFDDSIGVLQ
ANSQGFTPPGMDRSSPDNSPVHGMLRQPSITTGVNIPIITELVNDTNVQFLDQDDDDDPD
TELYLTQPFACGTAFAVSVLDSLMSATYFNDNILTLIRTLVTGGATPELEALIAEENALR
GGYSTPQTLANRDRCRVAQLALLDGPFADLGDGGCYGDLFCKALKTYNMLCFGIYRLRDA
HLSTPSQCTKRYVITNPPYEFELVPTDLIFCLMQFDSNSLEVLFQ

Ligands and cofactors

ID	Name	Formula	Copies
A1C9J	Penitrem A	C37 H44 Cl N O6	4
CLR	Cholesterol	C27 H46 O	28
AJP	Digitonin	C56 H92 O29	32
LBN	1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine	C42 H82 N O8 P	32

Water and common crystallization additives (K) are not listed.

Primary citation

Structural underpinnings of human Slo1 inhibition by scorpion and fungal toxins. Kallure, G.S., Pal, K., Prather, G.W. et al. Proc Natl Acad Sci U S A (2026) 123:e2606537123-e2606537123. DOI 10.1073/pnas.2606537123 · PubMed

Other PDB entries of the same protein (UniProt Q12791 (AlphaFold model), which also has an AlphaFold model), best resolution first:

6V5A 2.0 Å, Crystal structure of the human BK channel gating ring L390P mutant
8V60 2.43 Å, F315A mutant of human Slo1 in presence of EDTA - resting VSD
11DA 2.57 Å, Human Slo1-PenitremA complex under divalent chelated condition - full model
9CZM 2.57 Å, Ca2+ bound open-inactivated hSlo1 + beta2N-beta4 channel in nanodisc.
11CZ 2.6 Å, Human Slo1-paxilline complex under divalent chelated condition - full model
8V64 2.6 Å, RCK1-RCK2 double mutant of human Slo1 in presence of EDTA - resting VSD
8GHF 2.7 Å, cryo-EM structure of hSlo1 in plasma membrane vesicles
11DB 2.71 Å, Human Slo1-Paxilline complex under divalent chelated condition - gating-ring masked
8V63 2.72 Å, R207A mutant of human Slo1 in presence of EDTA - activated VSD
9JO3 2.8 Å, Cryo-EM structure of human BKca channel-compound 10b complex
8VAZ 2.82 Å, Structure of human Slo1 and human LRRC26 in EDTA - LRRD masked
9CZO 2.87 Å, Ca2+ bound intermediate state of hSlo1 + beta2N-beta4 channel in nanodisc.

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